Barrel length quwstion?


Well-Known Member
Jul 13, 2009
Border City (on the poor side}:-()
I know longer barrels add to your FPS.

My question is 2 parts.

1. How many FPS per inch do you loose on average?

2. How does barrel length affect max load pressure? Does a longer barrel with the same load have higher pressure or is it affected?
What Cal?? smaller cal less diference the longer it is......Over bore cals need longer and will gain more per inch

Saw an article on 6mmBR that tested between 28-33 inch and past 28" the average was around 8fps.....but they didn't test shorter unfortunatly
Dad's 7mm is 24 1/2" long & my 264 Win Mag is just over 26". You wouldn't think the extra 1 1/2 would be much of an issue in the field, but I find it somewhat clumsy & awkward compared to Dad's 7mm, especially going through light bush.

1 1/2" shorter on a 264 Win Mag shouldn't make much difference?
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Depends on several factors. Big overbore small caliber magnums can gain quite a bit with barrel length. Short efficient cartridges like the 6mm BR gain very little. For example my 257 and 264 STW's have gained as much as a 100 fps going from 26" to 28" of barrel length. My big 338's including the Lapua, 338-378 wby, 338 ulttramag and 338-300 ultramag average about 20 fps per inch. Powders and primers also affect barrel length velocity. Sometimes with a faster powder and hot primer to get all the burn quick as possible you can overcome some of the velocity loss in a shorter barrel. Lots of factors and there is no set velocity gain per inch of barrel. It will differ with each cartridge or class of cartridges.
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